Valve tappet push rod



y 1954 J. T. WRIGHT VALVE TAPPET PUSH ROD 2 Sheets-Sheet 1 Filed June 12, 1952 Fig.

Jesse 7. Wright IN VEN TOR.

May 4, 1954 J. T. WRIGHT VALVE TAPPET PUSH ROD 2 Sheets-Sheet 2 Filed June 12, 1952 IN V EN TOR.

Jesse 7. Wright vllll i Patented May 4, 1954 UNITED STATES PATENT OFFICE VALVE TAPPET PUSH ROD Jesse T. Wright, Bountiful, Utah Application June 12, 1952, Serial No. 293,178

8 Claims.

This invention relates in general to valve tappet push rods, and more particularly to a selfadjusting push rod that will expand longitudinally to compensate for wear.

The primary object of this invention is to provide an improved push rod for internal combustion engines which is provided with a slack takeup device whereby a rocker arm or other tappet may be in constant engagement with a valve stem and at the same time permitting the existence of a clearance between the positive drive of the cam shaft and the end of the valve stem Another object of this invention is to provide an improved push rod adapted for use with internal combustion engines having overhead valves whereby the lost motion between the rocker arms and the valve stems is eliminated, thereby eliminating excessive noise resulting from the striking of the rocker arms on the ends of the valve stems.

Another object of this invention is to provide an improved push rod for use with internal combustion engines, said push rod being formed in sections which are urged apart by spring means,

the movable portions of said sections being prest tional and having portions thereof urged apart by a spring element, said push rod being proi vided with means for locking the spring element in an inoperative position whereby the clearance between an associated rocker arm and valve stem may be properly adjusted.

With these objects definitely in view, this invention resides in certain novel features of construction, combination and arrangement of elements and portions as will be hereinafter described in detail in the specification, particularly pointed out in the appended claims, and illustrated in the accompanying drawings which form a material part of this application and in which:

Figure 1 is a fragmentary front elevational view of a conventional overhead valve internal combustion engine, portions of the block and valve cover of the engine being broken away and shown in section in order to clearly illustrate the construction of the valve assembly and the push rod, which is the subject of this invention;

Figure 2 is an enlarged fragmentary longitudinal vertical sectional view taken substantially upon the plane indicated by the section line 2-2 of Figure 1 and shows the elements of the .push rod in operative positions;

Figure 3 is an enlarged transverse horizontal sectional view taken substantially upon the plane indicated by the section line 33 of Figure 2 and shows the normal relationship of locking pins for portions of the push rod assembly;

Figure 4 is an enlarged fragmentary front elevational view of an upper portion of the push rod of Figure 1 and its associated rocker arm, the engine block and valve cover being shown in section, the spring for urging portions of the push rod apart being retained in an inoperative position by a locking device; and

Figure 5 is an enlarged transverse horizontal sectional view taken substantially upon the plane indicated by the section line 55 of Figure 4 and shows the relation of a pin carried by the locking device when the same is in a spring locking position.

Similar characters of reference designate similar or identical elements and. portions throughout the specification and throughout the different views of the drawings.

Referring now to the drawings in detail, it will be seen that there is illustrated in Figure l a conventional internal combustion engine, which is referred to in general by the reference numeral ID, of the overhead valve type. The engine includes a block l2 in which is mounted for rotation a cam shaft I4 having in engagement therewith a cam follower l6. Secured to the top of the block I2 is a head I8 on which is mounted a rocker arm shaft support and a longitudinally extending rocker arm shaft 22. Mounted on the rocker arm shaft 22 for pivotal movement is a rocker arm 24 which has one arm thereof in vertical alignment with the cam follower i6 and operatively connected thereto by a push rod 26. The other arm of the rocker arm 25 is adapted to engage the upper end of a valve stem 28.

It will be understood that the valve stem 28 has integral with the lower end thereof a valve (not shown) which is actuated by the rocker arm 24. In order that the valve stem and its associated valve may be raised to a closed position upon upward movement of the rocker arm 24, the valve stem has surrounding the same a valve spring 30 whose lower end bears against the upper surface of the head I8 and whose upper end bears against a keeper 32.

In order that proper seating of the valve may be assured, the upper end of the valve stem 28 is slightly spaced from a tappet portion 34 of the rocker arm 24 when the tappet portion 3% is in its uppermost position and the valve is seated. While the clearance between the upper end of the valve stem 28 and the tappet 34 is only a few end portions 3 thousandths of an inch, the striking of the tappet 34 in a downward stroke against the upper end of the valve stem 28 results in a noisy chatter. Also, the upward movement of the valve into engagement with its seat also results in additional noise.

Referring now to Figure 2 in particular, it will be seen that in order to retain the desired clearance between the positive drive elements for the valve stem28 and at. the same time to eliminate actual clearance between the tappet 34 and the upperend of the valve stem 28 whereby the chattering may be greatly reduced, the push rod 26 is sectional. The push rod 26 includes an upper tubular portion 36 which has engaged in the upper end thereof a reduced lowerportion ta of a rocker arm engageable member. The rocker arm engageable member 40 is provided with a shoulder 42 which is adapted to engage the upper end of the tubular portion 36 to insure a positive drive forpivoting the rocker arm '24.

Disposedinthe low-er endof the tubular portion -36 is a coil spring44 which urges the member 4fl upwardly with respect to the-upper-end of the tubular portion 36 whereby the tappet 34 is moved into engagement with the upper end of the valve stem 28 and the clearance eliminated at that point. However, -.it. will be understood that the shoulder v42 ofthe member-40 moves away from the upper end of the tubular portion 36 a distance equal to theclearance normally provided between the tappet 34 and the valve stem 28.

. Inasmuch-as the. strength of the valve spring 30 is much greater than that of the coil spring 44,

.thevalve associated with the-valv stem 28 will be permitted to seat.

spherical lower'end 50. 1 The spherical .lower end Ellis received in acomplementary seat 52 in the upper end ofuthemember lll andthe clearance between the tappet 34 .and the valve stem 28 .may be adjusted by threading the screw 48in or out of the threaded bore46. The.screw.48 is locked in its adjusted position by a lock nut 54 threadedly'eng-aged onthe upper. end thereof and engaging theupper surface of therocker. arm 24.

While the above described valve. assembly will operate in asuitable manner, it will beseen that the upward urging of the member 40 by the coil spring 44 results in th engagement .of the tappct 34 with the upperiend of the valve stem 28 whereby the normal clearance between-the two cannot be measured. Inasmuch as the internal combustion engine will not operate properly unless the valves are properlyset, it is desirable to provide means for rendering the coil spring 44 inoperative whereby the shoulder '42 ofthe member 40 engages the upper end of the tubular portion 36 and the clearance between the tappet 32 and the upper end of the valve stem 28 actually exists. In order to do so, the tubular portion 33 is provided with a spacer element 56 disposed between the upper end of the coil spring 44 and the lower end .of the reduced portion 38 of the member 41]. During normal operation of the push rod 26, the upward forceof the coil spring 44 is transmitted to the member .40 through the spacer '58. The spacer '56 is provided with, a transversely extendingpin 58which' is positioned with thereof extending outwardly stoodzthat the notches B2 are positioned below the normal position of the pin 58 whereby, when the same is moved downwardly into engagement therewith, the coil spring 44 is readily compressed.

Thetnotches 62 are so spaced from the normal position of the pin 58 whereby when the coil .spring44 and the spacer 56 are locked in position,

. the lowerend of the released portion 38 of the .of the tubular portion 38.

member 40 is spaced vertically above the upper .end .of the spacer 56 and the shoulder 42 of the member 40 is in engagement with the upper end After the valve has been adjusted, the pin 58 is rotated a slight angle back into the slot 60 where the same is free to reciprocate vertically. .It will be noted that the member .43 is also. locked to=the tubularportion 36 by a pin,64 which has end portions disposed within the slot 60.

Inasmuch as the reduced portion 38 of the member 40, the spacer..56 and the coil spring 44 reciprocate withinthe. tubular portion 36, it.is desirable that the elements be supplied with oil for lubricatingpurposesJ Therefore, therocker arm 24 is provided with an oil feed bore 66 which communicates with a transversely extending oil passage 68 in the screwl48. Thescrew .48 is provided with a longitudinaloil passage 10 which opens through the lower end of the spherical portion 50 and communicates with a longitudinal oil passage 12 through the member '43. The lower end of the longitudinal oil passage 12 communicates with a transversely extending oil passage 14 which applies oil to the. interior of the tubular portion 36. Inorder that oil may drain from the interior of the tubular portion 36, the bottom thereof is provided with a drain opening 16.

It will be understood that the push rod 26 may be used to replace existing push rods and that 'the'same, it not limited to use with the internal combustion engine illustrated in Figure l.

The'operation-of this device will be understood from the foregoing. description of the details thereof, taken in connection with the above recited objects and drawings. Further description as new is:

engageable with a cam follower, the upper portion of said elongated rod being tubular, a rocker arm engageable member carried by the upper end of the tubular upper portion, a spring carried by said tubular portion urging said member into engagement with the associated rocker arm, locking means for temporarily rendering said spring inoperative whereby the valve assembly may be adjusted to obtain the desired clearance, said tubular portion being provided with means for releasably retaining a portion of said member within said tubular portion for sliding movement.

3. A push rod for actuating a valve assembly comprising an elongated rod having a lower end engageable with a cam follower, the upper portion of said elongated rod being tubular, a rocker arm engageable member carried by the upper end of the tubular upper portion, a spring carried by said tubular portion urging said member into engagement with the associated rocker arm, looking means for temporarily rendering said spring inoperative whereby the valve assembly may be adjusted to obtain the desired clearance, said locking means being disposed within said tubular portion.

4. A push rod for actuating a valve assembly comprising an elongated rod having a lower end engageable with a cam follower, the upper portion of said elongated rod being tubular, a rocker arm engageable member carried by the upper end of the tubular upper portion, a spring carried by said tubular portion urging said member into engagement with the associated rocker arm, looking means for temporarily rendering said spring inoperative whereby the valve assembly may be adjusted to obtain the desired clearance, said locking means being disposed within said tubular portion between said member and said spring.

5. A push rod for actuating a valve assembly comprising an elongated rod having a lower end engageable with a, cam follower, the upper portion of said elongated rod being tubular, a rocker arm engageable member carried by the upper end of the tubular upper portion, a spring carried by said tubular portion urging said member into engagement with the associated rocker arm, locking means for temporarily rendering said spring inoperative whereby the valve assembly may be adjusted to obtain the desired clearance, said locking means including a transversely extending pin carried by said tubular member above said spring, said pin having end portions normally positioned in diametrically opposite vertical slots, each of said slots being provided with notches for receiving end portions of said pins to lock said spring in a compressed state.

6. A push rod for actuating a valve assembly comprising an elongated rod having a lower end engageable with a cam follower, the upper portion of said elongated rod being tubular, a rocker arm engageable member carried by the upper end of the tubular upper portion, a spring carried by said tubular portion urging said member into engagement with the associated rocker arm, looking means for temporarily rendering said spring inoperative whereby the valve assembly may be adjusted to obtain the desired clearance, said locking means including a transversely extending pin carried by said tubular member above said spring, said pin having end portions normally positioned in diametrically opposite vertical slots, each 01 said slots being provided with notches for receiving end portions of said pins to lock said spring in a compressed state, said notches being below the normal position of the pin.

7. A push rod for actuating a valve assembly comprising an elongated rod having a lower end engageable with a cam follower, the upper portion of said elongated rod being tubular, a rocker arm engageable member carried by the upper end of the tubular upper portion, a, spring carried by said tubular portion urging said member into engagement with the associated rocker arm, locking means for temporarily rendering said spring inoperative whereby the valve assembly may be adjusted to obtain the desired clearance, said locking means including a transversely extending pin carried by said tubular member above said spring, said pin having end portions normally positioned in diametrically opposite vertical slots, each of said slots being provided with notches for receiving end portions of said pins to lock said spring in a compressed state, said pin being carried by a spacer element disposed between and normally in engagement with said member and said spring.

8. A push rod for actuating a valve assembly comprising an elongated rod having a lower end engageable with a cam follower, the upper portion of said elongated rod being tubular, a rocker arm engageable member carried by the upper end of the tubular upper portion, a spring carried by said tubular portion urging said member into engagement with the associated rocker arm, look-- ing means for temporarily rendering said spring inoperative whereby the valve assembl may be adjusted to obtain the desired clearance, said locking means including a transversely extending pin carried by said tubular member above said spring, said pin having end portions normally positioned in diametrically opposite vertical slots, each of said slots being provided with notches for receiving end portions of said pins to lock said spring in a compressed state, said member having a lower portion thereof telescopically receive-d within the upper end of the tubular po tion and retained therein by a second pin having end portions disposed in said slots.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 649,444 Good May 15, 1900 1,605,494 Anderson Nov. 2, 1926 

